Fuel injection valves



March 22, 1966 B. H. CROFT FUEL INJECTION VALVES 2 Sheets-Sheet 1 Filed April 24, 1964 B. H. CROFT 3,241,768

FUEL INJECTION VALVES 2 Sheets-Sheet z March 22, 1966 Filed April 24. 1964 r/ wwa a rL 1 WAN 3 W \1 B MZM Fi g3 United States Patent 3,241,768 FUEL HNJECTKQN VALVES Brian Hugh Croft, Learnington Spa, England, assignor to Associated Engineering Limited, Warwiclrshire, England, a British company Filed Apr. 24, 1964, Ser. No. 362,385 Claims priority, application Great Britain, May 1, 1963, 17,176/ 63 Claims. (Cl. 239-12 9) The present invention relates to fuel injection valves for internal combustion engines.

It is an object of the present invention to provide an improved construction of electro-magnetically operated fuel injection valve.

The invention consists in an electro-magnetically operated fuel injection valve having a valve body which is adapted to be received within a cavity in a part of an engine, a valve stem located within the body and engaging a valve seating at one end and having an armature portion at its other end, wherein said armature is attractable by energisation of a solenoid to lift said one end of the valve stem from the seating to open the valve and allow fuel to flow through an outlet orifice, spring means for normally urging the valve stem into contact with the seating, a swirl chamber surrounding the valve stem upstream of the valve seating and at least one inlet port extending through the wall of the valve body and substantially tangential to the swirl chamber for feeding fuel to the swirl chamber.

Preferably the valve has a hollow valve stem and at least one port extending through the wall of the valve stem, so that when the valve is closed fuel can flow from the swirl chamber up inside the stem and through one or more return ports in the valve body back to the fuel supply for the valve. The port or ports through the wall of the valve stem and the tangential port or ports to the swirl chamber are non-aligned.

A restriction may be provided in the return .port or ports to control the rate of flow and swirl velocity of the fuel in the swirl chamber.

The spring means advantageously consists of an annular non-magnetic spring which extends over the head or armature end of the valve stem and acts as a spacer preventing intimate contact between the head of the valve stem and the face of the solenoid, as well as serving to urge the opposite end of the valve stem against the seating when the solenoid is de-energised. The solenoid may be formed as a separate assembly which is detachably secured to the upper end of the valve body.

In order that the invention may be more fully under stood, some embodiments thereof will now be described with reference to the accompanying drawings in which:

FIGURE 1 is a sectional view of one embodiment of electromagnetically operated fuel injection valve according to this invention,

FIGURE 2 is a section on the line 11-11 in FIG- URE 1, and

FIGURES 3 and 4 show modified constructions.

Referring to FIGURES 1 and 2, the fuel injection valve is illustrated as mounted in a cavity in a boss B provided in the wall of the inlet manifold of an internal combustion engine. The valve comprises a valve body generally indicated at 1, at the upper end of which is mounted a solenoid assembly 2 consisting of a coil 3 wound on an iron core 4. The coil and core assembly are contained within a housing 5 and are encapsulated in a synthetic resin material 6. The solenoid assembly is secured to the valve body by means of the screwthreaded retaining ring 7. The electrical connections to the solenoid are made by means of two terminals 8 whereby they are independent of any electrical connection to the casing of the engine.

The valve body 1 consists of a lower portion 1a which may be made of a bronze, a central portion 1b which may be made of brass and an upper portion 1c which may also be made of brass. The top end of the upper portion 10 is enlarged to receive the solenoid assembly 2. The three portions are secured together with an interference fit. The upper portion also carries an external screw thread 9 by means of which the valve body may be screwed into the cavity in the boss B; as well as an internal bronze guide sleeve 1d.

Within the valve body is arranged a valve stem 10 which has a central bore 11. The stem consists of a lower portion 10a made of a plastic material, such as that known under the trade name Delrin, an intermediate portion lllb which may be made of aluminium and an upper armature portion made of Swedish iron having an enlarged flat head 10d. These parts are also held together by an interference fit. The lower end of the valve stem is shaped to provide a seating surface 12a which engages with a seating surface 12b at the lower end of the valve body to close the valve. A central outlet orifice 13 is provided in the lower body portion In. An annular spring 14 of non-magnetic material is arranged at the upper end of the valve stem and extends from the outer part of portion 1c inwardly over the head 10d of the valve stem. This spring acts both to hold the seating 12a on the lower end of the valve stem engaged with the seating 12b and also acts as a spacer preventing intimate contact between the valve head 10d and the face of the solenoid. The air gap is accurately controlled by the thickness .of the spring.

Surrounding the lower end of the valve stem is a swirl chamber 15 to which fuel is fed through two holes 16 drilled substantially tangential to the swirl chamber. Three ports or apertures 17 are provided in the lower end of the valve stem to allow fuel to flow up through the hollow bore 11 of this stem and out through apertures 18 in the portion 100 and the return ports 21 in the body portion 10. The return ports may be provided with restrictions 21a.

Fuel is fed to the valve through the inlet connection 19 to a cavity 20 surrounding the valve body, and from thence through the holes 16 to the swirl chamber 15. Return fuel flowing through the return ports 21 is returned to the fuel reservoir through the outlet connection 22.

Sealing rings 23 are provided where shown to prevent leakage of fuel from the areas in which it is to be confined.

The operation of the fuel injection valve is as follows. When the valve stem is in the closed position with the seatings 12a and 12b in contact, no fuel flows through the orifice 13 to the engine manifold. However, the fuel will flow from the swirl chamber 15 through the bore 11 of the valve stem to the return fuel connection 22, hence fuel is continually rotating in the swirl chamber 15, which assists in providing good atomization during the initial stages of opening of the valve. When the valve is opened by energising the solenoid 2 and thus withdrawing the seating 12a at the lower end of the valve stem from the seating 12b, the fuel in the swirl chamber 15 flows through the central outlet Orifice 13 with a swirling component as well as an axial velocity component. This swirling causes the fuel to be passed through the orifice 13 as a thin film clinging to the wall of the orifice and having a central air core. On emerging from this orifice, the fuel forms a conical sheet which is atomized as it passes through the air. The fuel flow ceases when the solenoid is deenergised and the valve closes under the action of spring 14.

By adjusting the size of the restrictions 21a in the return ports 21, the rate of flow of fuel through the swirl chamber and the swirl velocity can be controlled.

According to a further embodiment of the invention, the ports 17 and 21 may be omitted so that there is no return flow through the hollow stern of the valve. In such an embodiment the swirl chamber can be made sufficiently large so that the body of fuel contained therein still tends to swirl for a time after the valve has closed, whereby some of the swirling motion is still present when the valve opens again, to assist in the rapid buildup of the thin film of fuel through the outlet orifice 13.

FIGURE 3 shows a modification wherein the lower end of the valve stem portion a is provided with a pin 24 projecting into the outlet orifice 13. This serves to improve linearity of the valve operation by controlling the initial flow and also reduces the dead volume of fuel present between the seating surfaces and the orifice 13, when the valve is closed, thereby preventing a large globule of fuel being fed from the valve when it first opens. The pin 24 can terminate either within the orifice, or beyond it as shown.

FIGURE 4 shows a modification in which the end of the valve stem portion 10a is shaped as at 25 to give a smoothly changing or constant flow area.

Fuel injection valves according to the present invention are simple to manufacture and possess the following advantages. The dual functions of fuel metering and fuel atomization are combined and the use of simple drilled holes is possible. Moreover the tangential holes 16 and the central orifice 13 combine to meter the fuel, and the fuel motion created by the tangential holes and the swirl chamber produces the correct conditions for atomization from a single orifice. Hitherto these two functions have generally been separated and necessitated the use of very accurately machined components of complicated shapes. The use of simple drilled holes allows manufacturing tolerances to be relaxed compared with such prior constructions.

Whilst particular embodiments have been described, it will be understood that various modifications may be made without departing from the scope of this invention. Thus instead of employing the form of return spring 14 as shown, a coil spring may be located within the bore 11 of the stem of the valve. Also it will be clear that the number of tangential holes and ports may be varied from those shown.

I claim:

1. An electromagnetically operated fuel injection valve having a valve body which is adapted to be received within a cavity in a part of an engine, a valve stem located within the body and engaging a valve seating at one end and having an armature portion at its other end, a solenoid for attracting said armature to lift said one end of the valve stem from the seating to open the valve and allow fuel to flow through an outlet on'fice, spring means for normally urging the valve stem into contact with the seating, a swirl chamber surrounding the valve stem upstream of the valve seating and at least one inlet port extending through the wall of the valve body and substantially tangential to the swirl chamber for feeding fuel to the swirl chamber.

2. A fuel injection valve as claimed in claim 1 in which the swirl chamber is located adjacent the valve seating.

3. A fuel injection valve as claimed in claim 1 having a hollow valve stem and at least one port extending through the wall of the valve stem so that when the valve is closed fuel can flow from the swirl chamber up inside the valve stem and through at least one return port in the valve body back to the fuel supply for the valve.

4. A fuel injection valve as claimed in claim 3, in which the at least one return port in the valve body is provided with a restriction to control the rate of How of fuel therethrough.

5. A fuel injection valve as claimed in claim 3, in which the at least one port in the valve stem is non-aligned with the at least one tangential port to the swirl chamber.

6. A fuel injection valve as claimed in claim 1, wherein the spring means consists of a non-magnetic spring which extends over the armature end of the valve stem and acts as a spacer preventing intimate contact between that end of the valve stem and the face of the solenoid as well as serving to urge the opposite end of the valve stem against the seating when the solenoid is de-energised.

7. A fuel injection valve as claimed in claim 1, including an extension projecting from the lower end of the valve stem into the outlet orifice in the valve body.

8. A fuel injection valve as claimed in claim 1, in which the valve body is provided with sealing means for forming fluid-tight joints between the valve body and the valve receiving cavity, when the valve is fitted in the cavity, in order to prevent leakage of fuel.

9. A fuel injection valve as claimed in claim 1, in which the solenoid is formed as a separate assembly which is detachably secured to the upper end of the valve body.

10. A fuel injection valve as claimed in claim 9, in which the electrical connections to the solenoid are made by means of terminal members attached to the solenoid and which are insulated from the valve body.

11. An electromagnetically operated fuel injection valve having a valve body which is adapted to be received within a cavity in a part of an engine, a hollow valve stem located within the body and engaging a valve seating at one end and having an armature portion at its other end, a solenoid for attracting said armature to lift said one end of the valve stem from the seating to open the valve and allow fuel to flow through an outlet orifice, non-magnetic spring means for normally urging the valve stem into contact with the seating, a swirl chamber surrounding the valve stem upstream of the valve seating, at least one inlet port extending through the wall of the valve body and substantially tangential to the swirl chamber for feeding fuel to the swirl chamber, and at least one port extending through the wall of the valve stem so that when the valve is closed fuel can flow from the swirl chamber up inside the valve stem and through at least one return port in the valve body back to the fuel supply for the valve.

12. A fuel injection valve as claimed in claim 11, in which the at least one return port in the body is provided with a restriction to control the rate of flow of fuel therethrough.

13. An electromagnetically operated fuel injection valve having a valve body which is adapted to be received within a cavity in a part of an engine, a valve stem located within the body and engaging a valve seating at one end and having an armature portion at its other end, a solenoid mounted at the top of said valve body for attracting said armature to lift said one end of the valve stem from the seating to open the valve and allow fuel to flow through the outlet orifice, non-magnetic spring means acting on said armature portion for normally urging the valve stem into contact with the seating, a swirl chamber surrounding the valve stem upstream of the valve seating, a plurality of inlet ports extending through the wall of the valve body tangential to the swirl chamber for feeding fuel to the swirl chamber, and a plurality of ports extending through the wall of the valve stem so that when the valve is closed fuel can flow from the swirl chamber up inside the valve stem and through at least one return port in the valve body back to the fuel supply for the valve.

14. A fuel injection valve as claimed in claim 13, in which the ports in the valve stem are non-aligned with the tangential ports in the swirl chamber.

15. A fuel injection valve as claimed in claim 13, including an extension projecting from the lower end of the valve stem into the outlet orifice in the valve body.

References Cited by the Examiner UNITED STATES PATENTS 1,323,778 12/1919 Lemp 239-585 5 2,315,172 3/1943 Voorheis 239-125 2,345,402 3/1944 Lubbock et al 239125 FOREIGN PATENTS 240,067 4/ 1946 Switzerland.

10 EVERETT W. KIRBY, Primary Examiner. 

1. AN ELECTROMAGNETICALLY OPERATED FUEL INJECTION VALVE HAVING A VALVE BODY WHICH IS ADAPTED TO BE RECEIVED WITHIN A CAVITY IN A PART OF AN ENGINE, A VALVE STEM LOCATED WITHIN THE BODY AND ENGAGING A VALVE SEATING AT ONE END AND HAVING AN ARMATURE PORTION AT ITS OTHER END, A SOLENOID FOR ATTRACTING SAID ARMATURE TO LIFT SAID ONE END OF THE VALVE STEM FROM THE SEATING TO OPEN THE VALVE AND ALLOW FUEL TO FLOW THROUGH AN OUTLET ORIFICE, SPRING MEANS FOR NORMALLY URGING THE VALVE STEM INTO CONTACT WITH THE SEATING, A SWIRL CHAMBER SURROUNDING THE VALVE STEM UPSTREAM OF THE VALVE SEATING AND AT LEAST ONE INLET PORT EXTENDING THROUGH THE WALL OF THE VALVE BODY AND SUBSTANTIALLY TANGENTIAL TO THE SWIRL CHAMBER FOR FEEDING FUEL TO THE SWIRL CHAMBER. 